Overall Objectives and Specific Aims The overall objective of this Facility Core is to provide both routine histology processing, as well as more specialized histochemical and immunohistochemical techniques to Center investigators. This Core also provides technical assistance, training, and consultations in histological techniques, necropsies and histopathological interpretation for Center investigators. The Specific Aims of Facility Core 3 are: 1. To provide histology processing, including paraffin embedding, staining, frozen sections, and other conventional histology techniques required by Center Members; 2. To continue developing novel necropsy, morphometry (sample collection, orientation and processing) and immunohistochemical approaches precisely adapted to the needs of Center Members; 3. To provide training, advice and consultation for morphology techniques and for the histo- and immunopathologic diagnosis of experimental lesions to Center Members; 4. To provide more formalized instruction in histopathology in the context of new initiatives of the Career Development Core; 5. To identify, develop and implement new techniques as needed to support the initiatives developed by the Integrated Health Science Facility Core.